Fabrication of thienoacene-based Organic Thin-Film Transistors with various interfacial layers

Organic Thin-Film Transistors (OTFTs) using thienoacene-based organic semiconductors with various insulating interfacial layers (IILs) between the organic semiconductor and the dielectric layer were investigated. A field-effect mobility and threshold voltage of OTFT without interfacial layer using C₈-BTBT were 1.85 cm²/Vs and -5 V, respectively. By inserting the IIL especially for 2nd polymer materials and SAM treatment, the threshold voltage of the OTFT was slightly shifted to low threshold voltage. However, by using high-k materials such as HfO₂ and Si₃N₄, the threshold voltage was increased to -0.8 V and -3.5 V, respectively. These results showed that threshold voltage is influenced by the using different interfacial layers due to the presence intermolecular interaction on the charge transports occur via a hopping mechanism at grain boundaries of organic semiconductor and dielectric interface.